Aflatoxin Bl (AFBl) is one of the most potent liver carcinogens known for experimental animals. This chemical is also present in the environment as a result of mold related spoilage of foods and commodities. Consumption of these foods results in high intake of AFBl by people living in many regions of Asia and Africa. A number of researchers have used classic epidemiological methods to examine the possible causal relationship between AFBl in the diet and liver cancer. While strong associations between AFBl exposure and liver cancer have been found, new technologies have only recently become available to monitor individual exposure and metabolism of aflatoxin Bl in people. These methods will facilitate the dissection of the role of viral agents, such as hepatitis B, from aflatoxins in the etiology of liver cancer. The development of biomarkers to assess the exposure to aflatoxin will help in efforts to limit the potential risk in human populations. In the following proposed study we will examine both seasonal and annual variabilities in aflatoxin intake, metabolism, urinary and albumin disposition in people living in the Gambia, West Africa who are at high risk to develop liver cancer. These studies will systematically probe the correspondence between dietary intake of aflatoxins with biological markers, such as excreted AFB-DNA adducts, oxidative metabolites in urine, aflatoxin Ml in human milk and covalently bound aflatoxin to serum albumin, to determine which of these markers have utility for non-invasively assessing the exposure status of people at high risk for liver cancer.